dm: remove dm_mutex after bkl conversion
This patch replaces dm_mutex with _minor_lock in dm_blk_close()
and then removes it.
During the BKL conversion, commit 6e9624b8caec290d28b4c6d9ec75749df6372b87
(block: push down BKL into .open and .release) pushed lock_kernel()
down into dm_blk_open/close calls.
Commit 2a48fc0ab24241755dc93bfd4f01d68efab47f5a
(block: autoconvert trivial BKL users to private mutex) converted it to a
local mutex, but _minor_lock is sufficient.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4ef066a..0de6921 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -32,7 +32,6 @@
#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
#define DM_COOKIE_LENGTH 24
-static DEFINE_MUTEX(dm_mutex);
static const char *_name = DM_NAME;
static unsigned int major = 0;
@@ -328,7 +327,6 @@
{
struct mapped_device *md;
- mutex_lock(&dm_mutex);
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
@@ -346,7 +344,6 @@
out:
spin_unlock(&_minor_lock);
- mutex_unlock(&dm_mutex);
return md ? 0 : -ENXIO;
}
@@ -355,10 +352,12 @@
{
struct mapped_device *md = disk->private_data;
- mutex_lock(&dm_mutex);
+ spin_lock(&_minor_lock);
+
atomic_dec(&md->open_count);
dm_put(md);
- mutex_unlock(&dm_mutex);
+
+ spin_unlock(&_minor_lock);
return 0;
}
